With the proliferation of communication devices and systems, people have multiple communication channels by which they can be reached and by which they can reach their contacts. Although these multiple communication channels provide great flexibility, this flexibility comes at the cost of simplicity. For example, if a person (e.g., the sender) wants to meet another group of people, he has to determine which of the multiple communication channels will be effective to reach each of the intended recipients, each of whom may be reachable by a different channel. Alternatively, he can set up plans well in advance, knowing that over time each of the people invited to a gathering (e.g., the targets) is likely access a communication channel (e.g., email) by which the invitation was provided. That is, if the sender sends an email to a group of contacts a week in advance of a planned meeting, it is likely that all of the contacts will access their email accounts during the week regardless of whether the invitation is sent to their personal, work, or other email address.
For certain types of people and for certain types of meetings, however, there is no single effective, efficient, and acceptable communication channel. For example, if a parent wants to notify other parents that his family is at the park, for example, he can email the other parents. This technique is efficient for the sender but may not succeed in notifying the targets in a timely manner. A series of phone calls, on the other hand, may be more effective at notifying the targets, but it is not efficient for the sender and it may be unwanted by the target (e.g., a target may be at work, eating dinner, disinterested in meetings at a particular location, or otherwise not interested in the phone call).
Existing social networking and location tracking services fail to provide appropriate notifications in a manner that reliably gains the target's attention.